Fennly
Food & symptom diary

Bloated after eating and no idea why?

Photograph your meal. Fennly breaks it into ingredients, learns from how you feel, and ranks the foods most likely behind your symptoms. Then it helps you prove it.

Free to download. Your data stays in the EU. Delete it any time.

Fennly showing ranked suspected food triggers, with lactose at the top

Three steps, about a minute a day

No weighing, no barcode hunting, no typing out every ingredient.

1

Snap your meal

Fennly recognises the dish and splits it into ingredients with their trigger categories. It knows a pizza is dough, cheese and tomato.

Meal photo broken down into detected ingredients
2

Say how you feel

Ten seconds in the evening. Bloating, cramps, fatigue, headache, skin. Or an acute entry the moment it hits.

Logging options: photo, voice, text, evening recap, acute entry
3

Meet your suspects

After a few days Fennly ranks what is statistically most likely behind your symptoms, with a confidence score for each.

Ranked list of suspected triggers with confidence scores

Why a plain food diary never worked for you

Intolerances do not behave like allergies. Fennly is built around how they actually work.

Delayed reactions

Symptoms often show up four to twelve hours later. Fennly looks across that window instead of blaming your last meal.

Dose, not presence

A splash of milk is fine, a latte is not. Fennly adds up the total load across the day rather than ticking a box.

Stress and sleep

A rough night makes almost everything worse. Those get factored in, so your lunch does not take the blame.

Fourteen categories

Lactose, fructose, sorbitol, fructans, histamine, gluten, caffeine, alcohol and more, tracked separately.

Works offline

Log anywhere, syncs when you are back online. Nothing is lost on a plane or in a basement restaurant.

Private by design

Hosted in the EU. Photos are only analysed after you explicitly agree. Export or delete everything in two taps.

A hunch is not an answer. So Fennly tests it.

When a suspect is strong enough, Fennly walks you through a proper elimination and reintroduction test: cut it for a set window, then bring it back, and read the verdict. That is the same method a dietitian would use, minus the paperwork.

Guided elimination test for lactose over seven days
Comparison of symptom load on days with and without a suspected trigger

See the difference, do not just feel it

Days with the suspect against days without, side by side. It is the moment most people stop guessing, and the chart you can hand to your doctor instead of trying to remember what you ate three Tuesdays ago.

Built for people who are tired of guessing

Whatever you already suspect, Fennly starts there and narrows it down.

BloatingIBSLactose intolerance Fructose malabsorptionHistamine intolerance Gluten sensitivityLow FODMAP diet RefluxUnexplained fatigue

Questions people ask

How does Fennly find which food causes bloating?

You photograph your meal and log how you feel. Fennly splits the meal into ingredients with their trigger categories, then looks for statistical patterns across several days. It accounts for delayed reactions of four to twelve hours, for total dose across the day rather than simple presence, and for stress and sleep. After a few days it ranks the most likely triggers with a confidence score.

Why does bloating appear hours after eating?

Food intolerances do not behave like allergies. Symptoms often show up four to twelve hours after the meal, which is why people usually blame the wrong one. A handwritten food diary cannot resolve a connection across that window, and this is the main reason plain food diaries fail.

Is this a medical diagnosis?

No. Fennly surfaces statistical patterns from your own food and symptom diary and labels them as suspects, not diagnoses. Confirming an intolerance needs a test, and anything persistent belongs in front of a doctor. Fennly is not a medical device and does not diagnose, treat or cure anything.

What does it cost?

The app is free to download. Fennly Pro unlocks unlimited meal analyses, the full report with a confidence score per suspect, the guided elimination test and management mode. It is 4.99 € a week, or a one time lifetime purchase if you would rather not subscribe.

Do I have to photograph everything?

No. A photo is fastest, but you can speak your meal or type it. Manual text entries work offline and do not use an analysis.

How long until I see something useful?

Usually four to five days of logging. Intolerances need a few repetitions before a pattern separates from noise, and Fennly says openly when it does not have enough data yet.

Where does my data live?

On servers in the EU. Meal photos are sent for analysis only after you grant explicit consent in the app, and they are not used to train anything. You can export or delete your account and every entry from Settings.

Which food intolerance triggers does Fennly track?

Fourteen categories, tracked separately: lactose, fructose, sorbitol, mannitol, fructans, GOS, histamine, gluten, caffeine, alcohol, capsaicin, fat load, sulphites and salicylates.

Stop keeping the diary in your head

One photo a day is enough to start. In a week you will know more about your gut than you did in the last year.

Free to download · EU hosting · Cancel any time

Fennly is not a medical device. It does not diagnose, treat or cure anything. It shows suspected triggers derived from your own entries and always asks you to confirm them with a test. If your symptoms are severe, persistent, or come with weight loss, blood or fever, please see a doctor rather than an app.